/*
 * Copyright 2001-2004 The Apache Software Foundation.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.log4j;

import org.slf4j.LoggerFactory;
import org.slf4j.Marker;
import org.slf4j.MarkerFactory;
import org.slf4j.spi.LocationAwareLogger;

/**
 * <p>
 * This class is a minimal implementation of the original
 * <code>org.apache.log4j.Logger</code> class by delegation of all calls to a
 * {@link org.slf4j.Logger.Logger} instance.
 * </p>
 *
 * <p>
 * Log4j's <code>trace</code>, <code>debug()</code>, <code>info()</code>,
 * <code>warn()</code>, <code>error()</code> printing methods are directly
 * mapped to their SLF4J equivalents. Log4j's <code>fatal()</code> printing
 * method is mapped to SLF4J's <code>error()</code> method with a FATAL marker.
 *
 * @author S&eacute;bastien Pennec
 * @author Ceki G&uuml;lc&uuml;
 */
public class Category {

    private String name;

    private org.slf4j.Logger slf4jLogger;
    private org.slf4j.spi.LocationAwareLogger locationAwareLogger;

    private static Marker FATAL_MARKER = MarkerFactory.getMarker("FATAL");

    Category(String name) {
        this.name = name;
        slf4jLogger = LoggerFactory.getLogger(name);
        if (slf4jLogger instanceof LocationAwareLogger) {
            locationAwareLogger = (LocationAwareLogger) slf4jLogger;
        }
    }

    public static Logger getLogger(String name) {
        return Log4jLoggerFactory.getLogger(name);
    }

    public static Logger getLogger(Class clazz) {
        return getLogger(clazz.getName());
    }

    /**
     * Does the obvious.
     *
     * @return
     */
    public static Logger getRootLogger() {
        return getLogger(org.slf4j.Logger.ROOT_LOGGER_NAME);
    }

    /**
     * Returns the obvious.
     *
     * @return
     */
    public String getName() {
        return name;
    }

    /**
     * Return the level in effect for this category/logger.
     *
     * <p>
     * The result is computed by simulation.
     *
     * @return
     */
    public Level getEffectiveLevel() {
        if (slf4jLogger.isTraceEnabled()) {
            return Level.TRACE;
        }
        if (slf4jLogger.isDebugEnabled()) {
            return Level.DEBUG;
        }
        if (slf4jLogger.isInfoEnabled()) {
            return Level.INFO;
        }
        if (slf4jLogger.isWarnEnabled()) {
            return Level.WARN;
        }
        return Level.ERROR;
    }

    /**
     * Returns the assigned {@link Level}, if any, for this Category. This
     * implementation always returns null.
     *
     * @return Level - the assigned Level, can be <code>null</code>.
     */
    final public Level getLevel() {
        return null;
    }

    /**
     * @deprecated Please use {@link #getLevel} instead.
     */
    final public Level getPriority() {
        return null;
    }

    /**
     * Delegates to {@link org.slf4j.Logger#isTraceEnabled} method of SLF4J.
     */
    public boolean isTraceEnabled() {
        return slf4jLogger.isTraceEnabled();
    }

    /**
     * Delegates to {@link org.slf4j.Logger#isDebugEnabled} method in SLF4J
     */
    public boolean isDebugEnabled() {
        return slf4jLogger.isDebugEnabled();
    }

    /**
     * Delegates to {@link org.slf4j.Logger#isInfoEnabled} method in SLF4J
     */
    public boolean isInfoEnabled() {
        return slf4jLogger.isInfoEnabled();
    }

    /**
     * Delegates to {@link org.slf4j.Logger#isWarnEnabled} method in SLF4J
     */
    public boolean isWarnEnabled() {
        return slf4jLogger.isWarnEnabled();
    }

    /**
     * Delegates to {@link org.slf4j.Logger#isErrorEnabled} method in SLF4J
     */
    public boolean isErrorEnabled() {
        return slf4jLogger.isErrorEnabled();
    }

    /**
     * Delegates to {@link #isEnabledFor(Level)}.
     *
     * @param p the priority to check against
     * @return true if this logger is enabled for the given priority, false
     * otehrwise.
     */
    public boolean isEnabledFor(Priority p) {
        return isEnabledFor(Level.toLevel(p.level));
    }

    /**
     * Determines whether the level passes as parameter is enabled in the
     * underlying SLF4J logger. Each log4j level is mapped directly to its SLF4J
     * equivalent, except for FATAL which is mapped as ERROR.
     *
     * @param l the level to check against
     * @return true if this logger is enabled for the given level, false
     * otehrwise.
     */
    public boolean isEnabledFor(Level l) {
        switch (l.level) {
            case Level.TRACE_INT:
                return slf4jLogger.isTraceEnabled();
            case Level.DEBUG_INT:
                return slf4jLogger.isDebugEnabled();
            case Level.INFO_INT:
                return slf4jLogger.isInfoEnabled();
            case Level.WARN_INT:
                return slf4jLogger.isWarnEnabled();
            case Level.ERROR_INT:
                return slf4jLogger.isErrorEnabled();
            case Priority.FATAL_INT:
                return slf4jLogger.isErrorEnabled();
        }
        return false;
    }

    /**
     * Delegates to {@link org.slf4j.Logger#trace(String)} method in SLF4J.
     */
    public void trace(Object message) {
        // casting to String as SLF4J only accepts String instances, not Object
        // instances.
        slf4jLogger.trace(convertToString(message));
    }

    /**
     * Delegates to {@link org.slf4j.Logger#trace(String,Throwable)} method in
     * SLF4J.
     */
    public void trace(Object message, Throwable t) {
        slf4jLogger.trace(convertToString(message), t);
    }

    /**
     * Delegates to {@link org.slf4j.Logger#debug(String)} method of SLF4J.
     */
    public void debug(Object message) {
        // casting to String as SLF4J only accepts String instances, not Object
        // instances.
        slf4jLogger.debug(convertToString(message));
    }

    /**
     * Delegates to {@link org.slf4j.Logger#debug(String,Throwable)} method in
     * SLF4J.
     */
    public void debug(Object message, Throwable t) {
        slf4jLogger.debug(convertToString(message), t);
    }

    /**
     * Delegates to {@link org.slf4j.Logger#info(String)} method in SLF4J.
     */
    public void info(Object message) {
        slf4jLogger.info(convertToString(message));
    }

    /**
     * Delegates to {@link org.slf4j.Logger#info(String,Throwable)} method in
     * SLF4J.
     */
    public void info(Object message, Throwable t) {
        slf4jLogger.info(convertToString(message), t);
    }

    /**
     * Delegates to {@link org.slf4j.Logger#warn(String)} method in SLF4J.
     */
    public void warn(Object message) {
        slf4jLogger.warn(convertToString(message));
    }

    /**
     * Delegates to {@link org.slf4j.Logger#warn(String,Throwable)} method in
     * SLF4J.
     */
    public void warn(Object message, Throwable t) {
        slf4jLogger.warn(convertToString(message), t);
    }

    /**
     * Delegates to {@link org.slf4j.Logger#error(String)} method in SLF4J.
     */
    public void error(Object message) {
        slf4jLogger.error(convertToString(message));
    }

    /**
     * Delegates to {@link org.slf4j.Logger#error(String,Throwable)} method in
     * SLF4J.
     */
    public void error(Object message, Throwable t) {
        slf4jLogger.error(convertToString(message), t);
    }

    /**
     * Delegates to {@link org.slf4j.Logger#error(String)} method in SLF4J.
     */
    public void fatal(Object message) {
        slf4jLogger.error(FATAL_MARKER, convertToString(message));
    }

    /**
     * Delegates to {@link org.slf4j.Logger#error(String,Throwable)} method in
     * SLF4J. In addition, the call is marked with a marker named "FATAL".
     */
    public void fatal(Object message, Throwable t) {
        slf4jLogger.error(FATAL_MARKER, convertToString(message), t);
    }

    public void log(String FQCN, Priority p, Object msg, Throwable t) {
        int levelInt = priorityToLevelInt(p);
        if (locationAwareLogger != null) {
            if (msg != null) {
                locationAwareLogger.log(null, FQCN, levelInt, msg.toString(), t);
            } else {
                locationAwareLogger.log(null, FQCN, levelInt, null, t);
            }
        } else {
            throw new UnsupportedOperationException("The logger [" + slf4jLogger + "] does not seem to be location aware.");
        }

    }

    private int priorityToLevelInt(Priority p) {
        switch (p.level) {
            case Level.TRACE_INT:
                return LocationAwareLogger.TRACE_INT;
            case Priority.DEBUG_INT:
                return LocationAwareLogger.DEBUG_INT;
            case Priority.INFO_INT:
                return LocationAwareLogger.INFO_INT;
            case Priority.WARN_INT:
                return LocationAwareLogger.WARN_INT;
            case Priority.ERROR_INT:
                return LocationAwareLogger.ERROR_INT;
            case Priority.FATAL_INT:
                return LocationAwareLogger.ERROR_INT;
            default:
                throw new IllegalStateException("Unknown Priority " + p);
        }
    }

    private final String convertToString(Object message) {
        if (message == null) {
            return (String) message;
        } else {
            return message.toString();
        }
    }

}
